Old version docs tend to offer you a redirect to more recent docs

Sadly, the docs, I've worked with (openstack and ansible) frequently, don't do this. They have a button to go to the latest version of the docs, but not to the equivalent page on the latest version. This means I have to find the equivalent page again, from the integrated search usually.

And yes, a lot can change between versions. New features can get added that solve your problems or older stuff can get removed.